import java.util.Arrays;
import java.util.Scanner;

public class Kaoshi {
    public static String func(String str){
        boolean[] flg = new boolean[255];
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            if (flg[ch]==false){
                stringBuilder.append(ch);
                flg[ch]=true;
            }
        }
        return stringBuilder.toString();

    }
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNextLine()) {
            String str = scanner.nextLine();
            String ret = func(str);
            System.out.println(ret);
        }
    }
    public static void lift(int m,int n){
        int[] array1 = new int[m+n];
        int[] array2 = new int[n];
        int lifta=0;
        int liftb=0;
        for (int i = 0; i < array1.length; i++) {
             lifta=array1[i]<array1[i+1]?array1[i] :array1[i+1] ;
             liftb=array2[i]<array2[i+1]?array2[i] :array2[i+1] ;
            if (lifta<liftb){
                array1[i]=lifta;
            }else {
                array1[i]=liftb;
            }
        }
    }
    public static void lift2(int m,int n){
        int[] array1 = new int[m+n];
        int[] array2 = new int[n];
        int i = m - 1;
        int k = m+n - 1;
        int j = n- 1;
        while (i>=0&&j>=0) {

            if (array1[i] > array2[j]) {
                array1[k] = array1[i];
                i--;
                k--;
            } else {
                array1[k] = array2[j];
                j--;
                k--;
            }
        }
        while (i>=0){
            array1[k]=array1[i];
            i--;
            k--;
        }
        while (j>=0){
            array1[k]=array2[j];
            i--;
            j--;

        }
    }


}
